This is a sixteenth note.
It lasts for one quarter of a beat.
There are four sixteenth notes in one beat.
There are 16 sixteenth notes in one bar of four four time.
Tap your foot on each beat and count mentally as you play.
Now try this example which contains sixteenth notes moving between two different notes.
This one uses 16th notes moving between three different notes.
Often in songs you will find two sixteenth notes grouped together with an eighth note as demonstrated in this example.
This well known American folk song is in the key of C and contains many sixteenth notes as well as the combined eighth and sixteenth figures presented in the previous example. Take it very slowly at first and only increase the tempo (speed) when you can confidently play all the notes cleanly and evenly.
This Country flavored cross harp solo is a real challenge. It contains many sixteenth notes along with bends and grace notes using bends and slides.
Here is an example which moves between eighth notes, triplets and sixteenth notes. Tap your foot on each beat and count the subdivisions as you play. Learn it one lick at a time if you have trouble with it.